Microwave-Assisted Synthesis of a Defect-Rich CuO Electrode for Selective Electrochemical CO<sub>2</sub> Reduction to C<sub>2+</sub> Products
Quhan Chen, Xiang Luo, Guohao Mu, Xinyi Mao, Hongfeng Yin, Edward Lester, Tao Wu
Abstract
High Resolution Image Download MS PowerPoint Slide Electrochemical reduction of CO 2 to valuable C 2+ chemicals using renewable energy is a crucial pathway for sustainable development, replacing traditional nonrenewable feedstocks. In this study, CuO-based materials were synthesized with and without microwave heating as electrocatalysts for CO 2 reduction. The CuO synthesized under microwave irradiation (MW-CuO) showed a similar morphology to the conventionally heated samples but exhibited a higher density of defect sites with increased grain boundaries (GBs). MW-CuO electrodes with a Cu 2+ and CO 3 2– reactant ratio of 1.1 showed superior catalytic performance under identical reaction conditions. In particular, the catalytic activity of the MW-CuO electrode at −1.04 V vs RHE for the C 2+ products is 49.3% higher than that of the CuO electrode. A faradaic efficiency (FE) of 71.9% is achieved for C 2+ products, which is among the highest yields reported for OD-Cu catalysts. The spent MW-CuO electrode exhibited a significantly higher Cu + to Cu 0 ratio compared to the CuO electrode. The synergy of Cu(I) species and defective surface features is speculated to be responsible for the improved CO 2 ER selectivity toward multicarbon products. However, the activity decreased for longer reactions, which was attributed to the loss of defect sites and Cu agglomerations. This study highlights the effectiveness of a simple synthesis approach for the production of defect-rich electrocatalysts that improve the efficiency and selectivity of CO 2 reduction.